Holding patterns are racetrack patterns applied in flight operations in various situations such as, for example:                For delaying arriving traffic in congested airspace.        In military aviation, tanker aircraft fly orbits to provide refueling services to other aircraft.        Military Airborne Warning And Control System (AWACS) aircraft can fly orbits for providing surveillance, control and communication services during military operations.        In case of a non-critical technical problem with an airplane without fuel dump capability, the flight will stay in a holding pattern until the aircraft weight drops below the maximum landing weight.        For relaying TV signals from ground during, for example, cycling events.        For observation missions above a certain area of interest (e.g. with unmanned aerial systems).        
Known holding patterns applied in arrival operations are mostly fixed. Holding pattern parameters (such as location, orientation and shape of the holding circuit) are typically predefined and published on the arrival charts. Air traffic control normally imposes an altitude and airspeed to be followed by the aircraft without taking into account fuel efficiency. Therefore, aircraft fuel consumption in current holding patterns is not optimized. In other situations where the airplane must rapidly consume fuel to reach an allowed landing weight, holding time is also not minimized.